1. Field of the Invention
This invention relates to structures of thin film magnetic write heads. More specifically, the invention relates to perpendicular thin film write heads for recording on media with or without soft under layers.
2. Description of the Related Art
Single pole tip write heads having trailing shields or wrap around shields are currently used for perpendicular recording. The media upon which data is written (for example, the hard disk in a hard disk drive) comprises a layered structure having various, layers. The upper layers contain a hard magnetic data layer, followed by non-magnetic layers, followed by a magnetic soft under layer. For reasons concerning future media development, it is desirable to eliminate the soft under layer. For reasons of compatibility and continuity in development, it is also desirable that new head designs be operable both with and without the soft under layers. However, for prior art write heads of convention construction having, for example, wrap around shields, removing the soft under layer results in a large return flux at the wrap around shield adjacent to the write pole. In the down track direction, this results in a large negative field following the maximum positive field at the trailing edge of the pole. This may result in unwanted erasure of data being written to the media. Additionally, cross-track field profiles show an increase in stray erasure fields of adjacent tracks when no soft under layer is present. Currently, no prior art design is suitable for perpendicular recording at high density without the presence of a soft under layer.
What is needed is a perpendicular thin film head design that is suitable for recording on media with or without a soft under layer.